Stability of the Stratification of Water Bodies in the North Passage of the Yangtze River Estuary Based on the EFDC Model

To study the stratified stability of a water column in the North Passage of the Yangtze River Estuary,a numerical model of the hydrodynamics of this estuary is established using the EFDC model.On the basis of EFDC results,this paper derives and pro-vides the discriminative index of water body stability caused by salinity and analyzes the along-range variation in water body strati-fication stability in the North Passage of the Yangtze River Estuary and the periodic variation at a key location(bend area)based on the simulation results of the numerical model.This work shows that the water body in the bend area varies between mixed and strati-fied types,and the vertical average flow velocity has a good negative correlation with the differential velocity between the surface and bottom layers of the water body.The model simulation results validate the formulae for the stratified stability discriminant during spring tides.

Development potential of the Northeast Passage based on a multinomial-logit-based stochastic user equilibrium model

We developed a multinomial-logit-based stochastic user equilibrium(MNL SUE)model incorporating time value of cargo to investigate future proportions of cargo flow through the Northeast Passage(NEP)and the Suez Canal Route between representative ports.We studied navigation during the ice-free and ice-covered seasons using sea ice projections for 2070 based on 1991–2021 NEP ice data.Sailing distance and time between selected ports are lower via the NEP than the Suez Canal Route.Under the scenario of year-round operation of the NEP,the proportion of cargo flow through the NEP is estimated to be 68.5%,which represents considerable commercial potential.Proportions are higher for the ice-free season and for ports at high latitudes.We also assessed flow under different scenarios.Under the scenario of fuel price increase,proportion of flow through the NEP in the ice-covered season is expected to increase.If time value is ignored,flow through the NEP is expected to increase all year round.If shippers become more cost-conscious,flow through the NEP is also expected to increase.

Optimization of transport passage with dragline system in thick overburden open pit mine

According to the characteristics of opencast coal resources and dragline technology system application in China,the structure and shifting step of transport passage are optimized in this paper.Typical coal transport passage is analyzed in aspects such as the internal dump occupation,dragline operation efficiency,coal transport distance,upper stripping distance and shifting quantities.The middle passage should be given priority in thick overburden open pit mine because the dragline system is only responsible for part stripping task.According to characteristics of middle passage,the transport passage is divided into parallel climbing,vertical climbing and horizontal transport.In addition,the transport passage structure optimization model and shifting distance optimization model are established in this paper.The case study in Heidaigou open pit mine shows that,the parallel climbing height is accounted for about 60%of the total height,and reasonable shifting distances of the first mining area and the second mining area are 240 and 320 m.Sensitivity analysis shows that,the total passage height has important influence on the shifting step,so it is with the stripping height and passage construction cost to the passage structure.

Failure of Aspired Understanding Among the Human Race——On the Theme of A Passage to India

The author attempts to interpret the theme of A Passsage to India by analyzing the major events and characterization. It is indicated in the thesis that E.M.Forster highlights the failure of aspired understanding between different races, different people and even within a person. In other words, in many cases people have aspirations for understanding, but in reality the real understanding is very difficult to fulfill.

An Analysis of the Performance of Orientalism in A Passage to India and the Exorcization of Orientalism in Maxine Hong Kingston's Works

This thesis tries to study two novels:firstly,the performance of Orientalism in the novel A Passage to India;secondly the Exorcization of Orientalism in the novel the Woman Warrior written by Maxine Hong Kingston.

A Preliminary Study on Historical Evolution and Spatial Characteristics of Traditional Settlements along the Feihu Passage Based on GIS

The eight Taihang passages are important cultural routes in the northern region,and a large number of traditional settlements with northern residential characteristics are distributed along the passages.Traditional settlements along the Feihu passage are studied in the paper,and the temporal and spatial distribution of traditional settlements is sorted out via ArcGIS platform,to explore its historical evolution in time and distribution rule in space.

Effects of Meridional Flow Passage Shape on Hydraulic Performance of Mixed-flow Pump Impellers

During the process of designing the mixed-flow pump impeller, the meridional flow passage shape directly affects the obtained meridional flow field, which then has an influence on the three-dimensional impeller shape. However, the meridional flow passage shape is too complicated to be described by a simple formula for now. Therefore, reasonable parameter selection for the meridional flow passage is essential to the investigation. In order to explore the effects of the meridional flow passage shape on the impeller design and the hydraulic performance of the mixed-flow pump, the hub and shroud radius ratio (HSRR) of impeller and the outlet diffusion angle (ODA) of outlet zone are selected as the meridional flow passage parameters. 25 mixed-flow pump impellers, with specific speed of 496 under the design condition, are designed with various parameter combinations. Among these impellers, one with HSRR of 1.94 and ODA of 90° is selected to carry out the model test and the obtained experimental results are used to verify accuracies of the head and the hydraulic efficiency predicted by numerical simulation. Based on SIMPLE algorithm and standard k-ε two-equation turbulence model, the three-dimensional steady incompressible Reynolds averaged Navier-Stokes equations are solved and the effects of different parameters on hydraulic performance of mixed-flow pump impellers are analyzed. The analysis results demonstrate that there are optimal values of HSRR and ODA available, so the hydraulic performance and the internal flow of mixed-flow pumps can be improved by selecting appropriate values for the meridional flow passage parameters. The research on these two parameters, HSRR and ODA, has further illustrated influences of the meridional flow passage shape on the hydraulic performance of the mixed-flow pump, and is beneficial to improving the design of the mixed-flow pump impeller.

Anisodamine accelerates spontaneous passage of single symptomatic bile duct stones ≤ 10 mm

AIM:To investigate the rate of spontaneous passage of single and symptomatic common bile duct(CBD)stones≤10 mm in diameter in 4 wk with or without a2-wk course of anisodamine.METHODS:A multicenter,randomized,placebocontrolled trial was undertaken.A total of 197 patients who met the inclusion criteria were enrolled.Ninetyseven patients were assigned randomly to the control group and the other 100 to the anisodamine group.The anisodamine group received intravenous infusions of anisodamine(10 mg every 8 h)for 2 wk.The control group received the same volume of 0.9%isotonic saline for 2 wk.Patients underwent imaging studies and liver-function tests every week for 4 wk.The rate of spontaneous passage of CBD stones was analyzed.RESULTS:The rate of spontaneous passage of CBD stones was significantly higher in the anisodamine group than that in the control group(47.0%vs 22.7%).Most(87.2%,41/47)stone passages in the anisodamine group occurred in the first 2 wk,and passages in the control group occurred at a comparable rate each week.Factors significantly increasing the possibility of spontaneous passage by univariate logistic regression analyses were stone diameter(<5 mm vs≥5 mm and≤10 mm)and anisodamine therapy.Multivariate logistic regression analyses revealed that these two factors were significantly associated with spontaneous passage.CONCLUSION:Two weeks of anisodamine administration can safely accelerate spontaneous passage of single and symptomatic CBD stones≤10 mm in diameter,especially for stones<5 mm.

Changes in sea ice kinematics in the Arctic outflow region and their associations with Arctic Northeast Passage accessibility

Amplification of climate warming in the Arctic is causing a dramatic retreat of sea ice, which means the Arctic sea routes are becoming increasingly accessible. This study used a satellite-derived sea ice motion product to quantify the kinematic features of sea ice in the Arctic outflow region which specially referred to the Fram Strait and to the north of the Northeast Passage(NEP). An observed trend of increased southward sea ice displacement from the central Arctic to the Fram Strait indicated enhancement of the Transpolar Drift Stream(TDS). In the regions to the north of the NEP, the long-term trend of northward sea ice speed in the Kara sector was +0.04 cm/s per year in spring. A significant statistical relationship was found between the NEP open period and the northward speed of the sea ice to the north of the NEP. The offshore advection of sea ice could account for the opening of sea routes by 33% and 15% in the Kara and Laptev sectors, respectively. The difference in sea level pressure across the TDS,i.e., the Central Arctic Index(CAI), presented more significant correlation than for the Arctic atmospheric Dipole Anomaly index with the open period of the NEP, and the CAI could explain the southward displacement of sea ice toward the Fram Strait by more than 45%. The impact from the summer positive CAI reinforces the thinning and mechanical weakening of the sea ice in the NEP region, which improves the navigability of the NEP.

Development and Application of a Shaft-type Tubular Pumping System with a Siphon Discharge Passage

Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.

Sensitivity analysis of the vane length and passage width for a radial type swirler employed in a triple swirler configuration

The design of axial or radial swirlers typically governs a number of geometrical parameters that are determined by the desired flow field.In the meantime,the number of unknown parameters increases with the number of concentrically mounted swirlers.The available literature is nonetheless limited,and designers are obligated to increase the number of initial assumptions.In this article,three kinds of triple swirlers are employed and simulations are performed to determine the effect of each parameter on the swirler performance.Based on the correlation provided,overlengthening the radial vane length could result in significant changes in the flow field from the jetlike pattern to a wide swirl-jet angle due to the Coanda effect.Passage width should also have the potential to alter the swirl-jet angle and velocity field at the exit of the swirler.

Effects of medication methods after simple and effective probing of lacrimal passage

AIM:To evaluate the effect of reducing the use of antibiotics in the treatment of infant bacterial dacryocystitis after probing of the lacrimal duct.METHODS:A total of 542 cases of children under one year old and accepting nasolacrimal duct probing treatment were divided into two groups, which were treated with topical and oral antibiotics, respectively.Conjunctival sac secretions were used as a control index of bacterial infection, whereas the disappearance of epiphora symptoms and lacrimal passage patency were used as cure indexes. The χ2test was used to compare enumeration and measurement data, and a statistical significance was set at P <0.05. The therapeutic effect on the two groups of postoperative patients was investigated.RESULTS:In the two study groups, no significant differences in gender, age and postoperative control of lacrimal sac infection were observed. The cure rates after three probing operations also showed no significant difference.CONCLUSION:After probing of the lacrimal passage,results of this study confirmed that postoperative medication without oral antibiotics but an ophthalmic dosage of antibiotics was a simple and effective treatment method.

The influence of the underpassing frozen connecting passage on the deformation of the existing tunnel

Based on the engineering background of the contact channel between Shangyang and Gushan of Fuzhou Metro Line 2 undercrossing the existing tunnel line,the freezing temperature field of the contact channel,the displacement field of the existing tunnel line and the contact channel with different net distances and horizontal angles are analyzed by ANSYS finite element software and field measurement method.The obtained results indicate that during the freezing period,the temperature drops at different measuring holes are almost the same.The temperature near the bottom freezing tube drops faster than that far from the tube.It is found that the bilateral freezing technique improves the formation of the freezing wall in the intersection area.In this case,the intersection time of the cross-section is 7 days faster than that of the adjacent ordinary section.The change curve of the displacement of the surface uplift in different freezing periods with the distance from the center of the channel is“M”shaped.The maximum uplift displacement at 12 m from channel center is 25 mm.The vertical displacement of the measuring point located above the central axis of the connecting channel is large.The farther the point from the central axis,the smaller the corresponding vertical displacement.When the horizontal angle between the existing tunnel and the connecting channel is less than 60,the existing vertical displacement of the tunnel changes rapidly with the horizontal angle,reaching 0.17 mm/.Meanwhile,when the net distance is less than 6.1 m,the change rate of the vertical displacement of the tunnel is up to 2.4 mm/m.

Influence of freeze tube deviation on the development of frozen wall during long cross-passage construction

This paper investigates the influence of the deviation in freeze pipe installation on the development of the frozen wall in long cross passages by numerical simulation with ANSYS software.The study case is from the artificial ground freezing project along the Fuzhou Metro Line 2 between Ziyang Station and Wuliting Station.Two freezepipe configurations,i.e.,one with perfectly aligned pipes without any deviation from design and another with randomly distributed deviation,are included for comparison.The effect of the random deviation in the freeze pipes on frozen wall interconnection time,the thickness of the frozen wall and the development of the temperature field is explored.For the characteristic section of the numerical model at a depth of 25 m,it is found that the frozen wall interconnection time under the random deviation case and no deviation case is 24 days and 18 days,respectively.The difference in the thickness of the thinnest frozen wall segment between the random deviation and no deviation cases is the largest in the early freezing stage(up to 0.75 m),which decreases with time to 0.31 m in the late freezing stage.The effects of random deviation are more significant in the early freezing stage and diminish as the freezing time increases.

Brownian Motion of Decaying Particles: Transition Probability, Computer Simulation, and First-Passage Times

Recent developments in the measurement of radioactive gases in passive diffusion motivate the analysis of Brownian motion of decaying particles, a subject that has received little previous attention. This paper reports the derivation and solution of equations comparable to the Fokker-Planck and Langevin equations for one-dimensional diffusion and decay of unstable particles. In marked contrast to the case of stable particles, the two equations are not equivalent, but provide different information regarding the same stochastic process. The differences arise because Brownian motion with particle decay is not a continuous process. The discontinuity is readily apparent in the computer-simulated trajectories of the Langevin equation that incorporate both a Wiener process for displacement fluctuations and a Bernoulli process for random decay. This paper also reports the derivation of the mean time of first passage of the decaying particle to absorbing boundaries. Here, too, particle decay can lead to an outcome markedly different from that for stable particles. In particular, the first-passage time of the decaying particle is always finite, whereas the time for a stable particle to reach a single absorbing boundary is theoretically infinite due to the heavy tail of the inverse Gaussian density. The methodology developed in this paper should prove useful in the investigation of radioactive gases, aerosols of radioactive atoms, dust particles to which adhere radioactive ions, as well as diffusing gases and liquids of unstable molecules.

Orientalism in A Passage to India

A Passage to India is the masterpiece of E.M.Forster and a classical work of anti-colonialism,which exposes the insuperable chasm between the Great Britain and India.The book is full of bitter irony,beautiful lyrics,meaningful symbol and far-reaching philosophical predict.Since it published,the book has been study on many points of view such as religion,politics,race and culture.It analyzes the existence of Orientalism in the work according to the Orientalism theory of Said.It exposes the blockade that exists in the process of cultural communication between the east and the west,thus finding a way for the establishment of harmony between the east and the west:equal dialogues,multivariate coexistence and mutually infiltration so as to achieve world harmony and great unity.

Orthogonal optimization of flow uniformity at exit section of elbow-inlet passages

Elbow-inlet passage is widely used in large drainage pumping stations.Flow uniformity at the exit section directly determines its hydraulic performance.Flow uniformity must be optimized to improve the operational efficiency of the large axial-flow pumping station.Modeling and numerical simulation methods were used to investigate the elbow-inlet passage,and the accuracy of the calculation results was verified.The key geometric parameters affecting the uniformity of the flow were optimized by the orthogonal experiment design.The optimal schemes were obtained and compared with the original scheme.The results show that flow uniformity V u after optimization is 95.41%,which is increased by 1.04%.The pumping station efficiency is increased by 1.89%,thereby confirming the applicability and accuracy of the proposed scheme,especially for the optimization of flow uniformity of the exit section of the elbow-inlet passage.

Production and detection of ultracold Cs_2 molecules via four-photon adiabatic passage

We study theoretically how to produce and detect the ultracold ground-state Cs2molecule from Feshbach state. Numerical calculations are performed by solving the quantum Liouville equation based on multilevel Bloch model. The producing efficiency reaches 55% and the detecting efficiency is 31%. The producing and detecting efficiencies are closely related to the Rabi frequencies of laser pulses. The decay of relevant electronic and vibrational states obviously reduces the producing and detecting efficiencies.